Method of making adhesives and product thereof



Patented Sept. 29, 1942 METHOD OF MAKING ADHESIVES AND PRODUCT THEREOFDavis Miller Wood, Tacoma, Wash.

No Drawing.

Application February 28, 1939,

Serial No. 258,947

11 Claims.

My invention relates to an improvement in the method of making anadhesive and the product thereof. My invention will be described in itsrelation to the manufacture of veneer panels.

U. S. Patent No. 2,088,019, dated July 27, 1937, to Jacob N. Wickert,entitled Secondary alkyl sulphates are claimed therein as neutralsulphate esters of a saturated higher branchedchain secondary,monohydric alcohol, having at least 8 or 13 carbon atoms in itsmolecule and having at least one alkyl side chain directly connectedwith the carbon atom of the main carbon chain spaced from the carbonatom to which the sulphate group is attached. By using this product Ihave made a basic glue.

' Tergitol 4 and Tergitol '7 are made according to great improvement ina said patent, and are defined and described for the purposes hereof assecondary alkyl sulphates.

Tergitol 4 is -a secondary alkyl sulphate containing 14 carbon atoms andis sodium tetradecyl sulphate, and Tergitol '7 is a secondary alkylsulphate containing 1'l carbon atoms, and is sodium heptadecyl sulphate.These are the chemical names of the Tergitols I prefer to use, and arepurchasable in the open market under such names.

However, I have discovered that secondary alkyl sulphates containing asfew as 12 carbon atoms produce a decided beneficial effect in the gluesdescribed herein.

It is to be understood thatmy said invention is not confined to thespecific application of glueing together wood veneers to make veneerpanels, but is useful in all circumstances where it is desired to securea glue or adhesive which possesses the qualities of producing a smoothreadily spreadable, long working-life glue, having great adhesiveness, ahigh water resistant bond, and of substantial uniform viscosity, and aglue which will avoid much checking and surface stain when applied tothin wood surfaces, and a glue which will reduce the cost whileattaining great wet and dry strength.

All of these qualities appertain to a glue or glues made by mydiscovery, and to a far greater extent than to glues heretofore madewhich em.- ploy vegetable flour of a high protein content, as hereindescribed, as a predominate ingredient in quantity.

Seed base, as used herein, is the flour or meal made from vegetableseed, beans or ,nuts from which a large portion of the oil has beenextracted, and which flour or meal contains from 35% to 50%, orthereabouts, of protein.

When there is added to, or substituted for a part of, a seed base,animal proteins, such as casein or blood albumen, I will designate thecomposition as a blend base."

I mention soya bean flour and peanut flour as among the flours which Ican use, and coming within the definition of a "seed base, but othervegetable flours having substantially the protein content abovementioned can be used. To either the seed base" or the blend base isadded the following:

Lime, caustic soda, sodium silicate, carbon bisulphide or itsequivalent, or carbon bisulphide and carbon tetrachloride, which I willhereafter refer to as carbon bisulphide-tetrachloride dope, and to themmay be added alkali metal salt which when'used with lime by doubledecomposition produces causticity; and pine oil, and water. The abovementioned ingredients, or the proportions of'the above mentionedingredients, may be varied, and the glue made therefrom come within theterm basic glue.

Glues comprising the foregoing seed base or blend basefand chemicalslast above mentioned I will call basic glue. To illustrate a basic glueformula now very commonly used in the. manufacture of veneer panels thefollowing formula is given:

' Pounds Soya bean flour Lime -'l Caustic soda 9 Silicate of so 30Carbon bisulphide-tetrachloride dope-.." 2

Waters "cs0 to 365 Another formula for basic glue is substantially asfollows:

9 Pounds Soya bean flour 93.5 Trisodium phosphate 1.5 Sodium carb 5 Lime15 to 20 Caustic soda Silicate of soda Carbon bisulphide-tetrachloridedope 2 Aldehyde compound, made according to Patent No. 1,950,060 2 Water350 to 365 similar formulae employ peanut flour in place of some or allof the soya ,bean flour, and some have a percentage of casein or bloodalbumen substituted for a like percentage of flour, and some have "pineoil" added.

My invention is an improvement on all such "blend base" in the basicglue," a decided change takes place in the basic glue," (normally 0.25%to 0.5% is uniformly satisfactory) in that the texture of the basic glueis changed from a grainy nature, resembling bean soup, to a smooth andungrainy structure, resembling varnish in texture; the applicability ofthe glue made according to my invention to veneers in a mechanicalspreader is facilitated; the strength of the glue bond is increased ashereinafter stated; the working life of my improved glue is lengthenedapproximately three times that of "basic glues." As hereinafter statedthe quantity of seed base or blend base to spread 1000 square feet of 3-ply panels is less thanrequired to spread 1000 square feet of 3-plypanels when using the basic glue; and the staining and checking of thepanels is reduced.

Such basic glue requires from 27 lbs. to 30 lbs. of seed base or blendbase" in a "basic glue to spread 1000 square feet of 3-ply panels to getits maximum stick; whereas, myfimproved glue made according to myinvention, as hereinafter. set forth, will spread 1000 square feet of3-ply panels with some lbs. to 26 lbs. of "seed base or blend base toget its maximum stick? The working life" of glue means the time duringwhich the glue retains substantially its maximum strength andspreadability after it is tory to being put into a press. Pressing isrequired to bring the wood surfaces into intimate contact with the gluewhich has beenapplied to hold together the veneer composing the panels.

Pressure must be exerted before the glue in the lower panels of thestack loses any substantial part of its adhesive qualities, failingwhich there is produced an inferior or faulty panel or panels in thelower part of the stack. In plant practice frequently more than minutesis desirable to make up a stack of panels for pressing. About 10 minutesafter a basic glue is applied to the panels the adhesive quality thereofcommences to decrease and the ordinary time after basic glue is appliedwhich is considered safe to insure a good joint before applying pressureis not over 30 minutes after the glue is spread upon the veneer panels.Glue made according to my improved glue and "zinc sulphate glueinventions (as hereinafter defined) retains its adhesive qualitieslonger (that is, the "working life), and is as strong or stronger afterthe panels are spread for 30 minutes and before pressure than a basicglue is after standing 10 minutes in the panels. Thus the working lifeof glue made according to my invention far exceeds the working life of abasic glue. This important improvement in working life has been longdesired by manufacturers of veneer panels, and has been accomplished bymy invention.

To obtain the maximum adhesion of a basic glue it has been heretoforerequired that the having been found that the finer the seed base" isground the better adhesion is obtained in a basic glue. By means of myinvention I have found that a seed base ground from to mesh produces aglue superior to a basic glue employing a seed base ground to mesh inits adhesive qualities, and ease of spreading, and otherwise, as hereinpointed out. Thus there is a saving in time and expense in preparing aseed base" to be used in glue made according to my discovery over thetime and expense of preparing such seed base" used in a basic glue.

A'common test to determine the water resistance of glue when panels aremade up and pressed is as follows: After the glue has set test pieces ofwood panels are sawn so as to permit one square inch of 3-ply panels tobe used for break tests, and thereafter are subject to soaking in waterfor 48 hours. The panels so sawn and soaked are placed in a machine andsubjected to a pull which is measured by a scale, and the strength ofthe glue joint is noted in pounds per square inch. For a test of drystrength a similar method is pursued, except the soaking is omitted.

By means of using a Tergitol (without water soluble metallic sulphate) Ihave succeeded in raising the strength of the glue bond by glue madeaccording to my discovery above the strength of a basic glue." A basicglue, such as herein described, produces an average dry test pull ofabout 171.5 pounds, with a minimum of about pounds and a maximum ofabout 200 pounds. By means of my discovery, by the use ofTergitol alonewith "basic glue, the dry test strength of a basic glue" has been raisedto an average of about 232 pounds, with a minimum of about 210 poundsand a maximum of about 245 pounds.

Thus there is shown an improvement in the dry test of the glue madeaccording to my discovery of about 60 pounds better than a basic glue,or an increase of about 35% in dry strength.

The average wet test strength of a basic glue is about 98.5 pounds, witha minimum of 80 pounds and a maximum of about 120 pounds. Glue madeaccording to my discovery, by the use of Tergitol alone in a basic glue,has an average wet strength of- 113.5 pounds, with a minimum of 80pounds and a maximum of pounds, thus showing an increase of average wetstrength of 14%.

Instead of the glue made according to my dis- I covery by the use ofTergitol alone in a basic glue becoming less strong (as is the case witha basic glue) by the lapse of 30 minutes after being spread, the drytest strength of my glue at 30 minutes was 219 pounds, with a minimum of185 pounds and a maximum of 265 pounds, and a wet test strength of 128pounds, with a minimum of 115 pounds and a maximum of pounds. Thus thereis shownan increase of dry strength in my glue after the panels arespread with it for 30'minutes before being pressed of 34% plus, and awet strength of 38%. The result of the tests above given were obtainedfirst by making a basic glue, consisting of the following:

Pounds Soya bean flour 100 Water 360 Caustic soda dissolved in 10 lbs.of water--- 8 Lime suspended in 25 lbs. of water 7 Sodium silicate 25Carbon bisulphide-tetrachloride dope 2 seed base" be ground to 110 meshor finer, it 75 and then by making an exactly similar basic glue towhich Tergitol 4 in the amount of about 0.25 pound of 'Tergitol 4 wasincorporated, by which addition the glue which I designate as improvedglue is produced. 5

Other examples of glue formulae using my invention of improved glue andmethod of making same, which I find produces similar superior results tothose above mentioned, are as follows:

As a dry mixture, viz:

Example 1 Pounds Soya bean flour 99 Tergitol 4 or Tergitol l 0.25

Example 2 Pounds Soya bean flour 98 Pine oil 1v Tergitol 4 or Tergitol 70.25 Example 3 Pounds Soya bean flour 98 Sodium dibromate or sodiumphosphate--- 1 Tergitol 4 or Tergitol '7 0.25 Pine oil 0.9

Example 4 An example of "blend base glue which will produce superiorresults is as follows:

V Pounds Soya bean flour 90 Casein 5 Blood albumen 5 Tergitol 4 orTergitol 7 0.25

Example 5 Another example of blend base glue, such as is described inExample 4, above, would be to eliminate from Example 4, 5 lbs. of theblood 4 albumen or casein and correspondingly increase the soya beanflour or peanut flour; or instead of 5 lbs. blood albumen and 5 lbs.casein, use 10 lbs. of casein or 10 lbs. blood albumen, or a lesser orgreater number of pounds thereof, and cor-' respondingly modify the soyabean flour or peanut flour so that the total mixture of soya bean flouror peanut flour and casein and/or blood albumen would equal about 100lbs.

To each of the "dry mixtures, as shown in 0 the above Examples 1 to 5, Iadd the following, varying the proportions somewhat if desired, viz:

Carbon bisulphide-tetrachloride dope About 2 Where a Tergitol, such asdescribed, is incorporated in the formula of a dry mixture, as shown inthe examples last above mentioned, it may be eliminated therefrom, andmay be added to the water at the start, 'or during the process ofmixing. In such examples peanut flour and other proteinous'flours, asdescribed herein, may be used instead of soya flour.

The improved glue which I have made by means of incorporating one ormore of the Tergitols in a basic glue I will hereinafter call myimproved glue. r

I have found that by means of incorporating I sulphate glue strongerthan the basic glue.

As examples of a typical glue (which I will hereinafter call zincsulphate glue) which I have found to produce the improvement over thebasic glue and improved glue, as above described, are the following:

. Pounds 'Soya bean 'flour or peanut flour 97.4 Zinc sulphate 2.5Tergitol 4 or Tergitol 'l g 0.25 Water at roughly 70 F. (or at summertemperature. The matter of temperature is not essential, but asubstantially similar temperature produces a more uniform time forchemical action than would be the case with wide variations in watertemperature) 360 Caustic soda dissolved in 10 lbs. of water 8 Limesuspended in 25 lbs. of water 7 Sodium silicate 25 Carbonbisulphide-tetrachloride dope 2 An example of typical zinc sulphate glueemploying a blend base which will produce com parable results is asfollows:

- Pounds Soya bean flour or peanut flour 87.4 Casein 5 Blood alb n' 5Zinc sulp 2.5

Tergitol 4 or Tergitol 7 0.25, Water at roughly 70 F.-. 360 Caustic sodadissolved in 10 lbs. of water 8 Lime suspended in 25 lbs. of water 7Sodium silicate 25 Carbon bisulphide-tetrachloride dope 2 Anotherexample of zinc sulphate glue 'employing a blend base would be toeliminate in the above formula 5 pounds of either casein or bloodalbumen, and correspondingly increase thesoya .basic glue using a seedbase to which has been added one of the Tergitols and zinc sulphate madeaccording to the formula of the foregoing example shows the average drystrength of such glue to be 265 pounds, the average wet strength of suchglue to be pounds. For the purpose of comparison, the following table isset forth:

"Basic glue" Average dry strength Average wet strength 171.5 pounds 98.5pounds Basic glue plus Tergitola (My improved glue) 232 pounds 113pounds Basic glue plus Tergitol: and zinc sulphate (zinc sulphate glue")265 pounds 150 pounds In the matter of the dry test strength, my zinc isapproximately 64% plus In the matter of wet strength my Zinc sulphateglue" is appfoximately 51% plus stronger than the basic g ue.

In the matter of dry test strength my zinc sulphate glue isapproximately 14% plus stronger than my' improved glue. 'In the matter.of wet test strength my "zinc sulphate glue is approximately 40% plusstronger than my improved glue." In addition to the increase in both dryandwet strength in my zinc sulphate glue over said basic glue andimproved glue, I find that by means of employing Tergitol in the gluewith the zinc sulphate I control the action of the zinc sulphate in thequantities used by me. sulphate (without the Tergitol) in the quantitiesused by me is used with a basic glue, its action within the glue causesan erratic and unpredictable result. On some occasions it thickens theglue too quickly for use in ordinary mill practice, whereas, with thecombination of Tergitol and zinc sulphate with the basic glue," the glueis thinned as compared with. basic glue with zinc sulphate therein, andthe endresult is uniform and reliable, and the beneficial effect aspointed out herein is certain and predictable.

My zinc sulphate glue will spread 1000 square feet of 3-ply panels withthe use of but from to 24 pounds of seed base," whereas, the basic gluerequires from 27 to 30 pounds of seed base to spread 1000 square feet of3-ply panels. Thus my zinc sulphate glue requires 6 to 10 pounds lessseed base per 1000 square feet of 3- ply panels than the basic gluerequires, and effects thereby a great cost saving over "basic glue," orabout of the cost of seed base. As there are used in the plywoodindustry hundreds of tons a month of seed base glues, and blend baseglues, the aggregate saving by my improved glues is a very materialconsideration. My "zinc sulphate glue" has the quality of retaining itsviscosity practically at a uni form level much longer than basic glue,thereby increasing its working life and avoiding waste of glue whendelay occurs at the veneer plant after mixing the glue in the gluemixer.

The viscosity of my zinc sulphate glue has a range of from 60 to 85during 3 hours on a MacMichael viscosimeter as compared under likeconditions with a basic glueof from 60 to 280 in 85 minutes. The basicglues working If 'zinc salt to replace a part phates of Groups 3, 4 and5 of the Fresenius System.

When employing zinc sulphate, for example, in my zinc sulphate glue Iuse quantities thereof of 1.5% to 9% of the seed base or blend base andfind that a ratio of 2.5 pounds of zinc sulphate to 95 to 100 pounds ofseed base or blend base will yield the numerous beneficial resultsherein set forth when a Tergitol is present in the amount of about 0.25%of the seed base or blend base, although a greater quantity may be usedfor a Tergitol is fast to lime and the acids and alkali of the glue.

It is understood that these formulae are examples only,'and that I mayuse instead of soya flour varying kinds of vegetable flours containirigsubstantially the amount of protein as above set forth, for example,peanut flour or cotton seed flour, and that I do not confine the scopeof my invention to these examples only, as I may vary the proportions ofany of the ingredients in either my "improved glue or in my zincsulphate glue"; for example, I may use an alkali or all of the causticsoda and may use any one of the Tergitols as herein described, and maydiffer the proportions thereof to produce a glue of varying qualities tomeet the requirements of the trade and the variations in the quality ofthe "seed base."

I have found it convenient to mix together, for instance, soya beanflour, Tergitol in dry form, and the metal sulphate of Groups 3, 4 and 5of the Fresenius System (and pine oil, if used) approximately 3 minutes;

life is limited to about 50 minutes, whereas, my

zinc sulphate glue" has been used with satisfactory results afterstanding mixed in the glue pot over night. The increased working life isimportant in plant practice, and has long been sought by manufacturersof plywood.

In practicing my invention I prefer to use zinc sulphate because it iscommercially readily available, and is likewise low in cost. However,any compound having the characteristics of zinc sulphate in a glue mixmay be used with similar results. Among the many equivalents of zincsulphate in practicing my invention are the sulphates of such metals asaluminum, iron, cad- -mium, copper, and the like.

The water soluble metallic sulphates which I have discovered improve myimproved glue are designated in Groups 3, 4 and 5 of the FreseniusSystem. Ofthese I find iron sulphate makes the least improvement in myimproved glue. For the purpose of defining such water soluble metallicsulphates in these specifications and in the claims I will use thephrase water soluble metallic sulproximately 3 minutes;

at the same time the seed base" is ground, for thus they may be packedin convenient shipping units and be readily handled in packages ofappropriate size for a predetermined batch of glue.

In usual practice, the flour, Tergitol, metallic sulphate of Groups 3, 4and 5 of the Fresenius System and sometimes alkali salts are introducedat the glue plant into a glue mixed containing about 360 pounds of waterand stirred for from 3 to 5 minutes; thereafter is added the limesuspended in water, then stirred for apthereafter is added the water andstirred for thereafter is added the sodium silicate and stirred forapproximately one minute; thereafter is added carbonbisulphidetetrachloride dope and stirred for approximately 5 minutes.Then the glue is ready for use, the total mixing time being about 17minutes, thus shortening the ordinary time of mixing basic glue" byabout 5 minutes.

Whenever any of the Tergitols are used in solution I find it preferable,although not imperative, to introduce the same into the water beforeseed flour is added.

Other modes of applying the principle of my invention may be employedinstead of those explained above, the change being made as regards thedetails herein disclosed, provided the procaustic soda dissolved incedure or ingredients stated or the equivalents of such statedingredients or procedure, are employed. The particular order in whichthe fiour and several of the ingredients mixed in the formulas given byme in the making of glue according to my invention may be varied, and itis not necessary that the manufacture of the product be completed in asingle operation.

By giving ,the explanation and illustrations aforesaid, I do not intendto limit or indicate the use of my glue as confined to the applicationof my glue as explained and illustrated. For a glue made in accordancewith the principles of my invention may be used where. a glue isdesirable having the qualities of my invention.

When I use the term carbon bisulphidetetrachloride dope in thisspecification it is to be understood that I mean one of the severalagents used in the glue industry under that name. I prefer to use carbonbisulphide-tetrachloride dope as it is readily and cheaply obtainable,and has been quite uniformly used in the basic glues.

A typical dope is comprised of from 50 to-75 parts of carbon bisulphideand from 25 to 50 parts of carbon tetrachloride. From 1- to parts ofresin, such carbon bisulphide-tetrachloride as rosin, is sometimes'usedto replace an equal ride used with carbon bisulphide is introduced forthe purpose of preventing its ready ignition, and a small portion ofrosin may be used or not, as the theory of. using the rosin is to lessenthe escapement of carbon bisulphide fumes in the mixing of the glue, butneither the carbon tetrachloride nor the rosin is essential.

Having described my invention, what I claim and desire by Letters Patentis:

1. An adhesive composition which comprises the reaction product ofproteinaceous glue of at least one of the class consisting of vegetableseed flour of considerable protein content, casein, soluble bloodalbumin, and a secondary alkyl sulphate. of the class containing from 12to 1'7 carbon atoms inclusive, in an amount resulting in an increasedspreadability, working life, strength and water resistance of theadhesive,

and a water soluble metallic sulphate of Groups 3, 4 and 5 of theFresenius System in an amount to increase water resistance, strength,spreadability and workinglife of the resultant adhesive.

2. "An adhesive composition which comprises the reaction product of aproteinaceous glue of at least one of the class consisting of vegetableseed flour of considerable protein content, casein, soluble bloodalbumin, and a secondary alkyl sulphate of the class containing from 12to 17 carbon-atoms inclusive.

3. An adhesive composition which comprises the reaction product of aproteinaceous glue of at least one of the class consisting of vegetableseed flour of considerable protein content, caseflour of considerableprotein content, casein, soluble blood albumin, and a secondary alkylsulphate of the class containing from 12 to 17 carbon atoms inclusive,the proportion being from 0.05% to 2% to 100 pounds of the proteinaceousmaterial in such glue, and from 2 to 5 pounds of a water solublemetallic sulphate of Groups 3, 4 and 5 of the Fresenius System to 100pounds of the proteinaceous material. in the resultant glue.

6. A process of making an adhesive which comprises combining thereaction product of a proteinaceous glue of at least one of the classconsisting of a vegetable seed flour of considerable protein content,casein, soluble blood albumin, and a secondary alkyl sulphate of theclass containing from 12 to 17 carbon atoms inclusive, the proportionbeing 0.05 of a pound to 2 pounds in 100 pounds of proteinaceousmaterial of the resultant glue, and 2 to 5 pounds of a water solublemetallic sulphate of groups 3, 4 and 5 of the Fresenius System to 100pounds of the proteinaceous material in the resultant glue.

7. An adhesive composition which comprises the reaction product of aproteinaceous glue'of at least one of the class consisting of vegetableseed flour of considerable protein content, casein,

' soluble blood albumin, a small portion of a secondary alkyl sulphateof the class containing from 12 to 17 carbon atoms inclusive, and from 2to 5 pounds of a water soluble metallic sulphate of groups 3, 4 and 5 ofFresenius System in 100 pounds of proteinaceous material in theresultant,

glue.

8. An adhesive composition which comprises the reaction product of aproteinaceous glue of at least one of the class consisting of avegetable 0.05% to 2% of 100 pounds of the proteinaceous in, solubleblood albumin, and a secondary alkyl comisting of vegetable seed flourof considerable protein content, casein, soluble blood albumin, and asecondary alkyl sulphate of the class contaming from 12 to 1'7 carbonatoms inclusive,

the proportion thereof being 0.05 pound to v2 pounds in 100 pounds ofthe proteinaceous material in the resultant glue. i

5. An adhesive composition which comprises the reaction product of aproteinaceous glue of at least one of the class consisting of vegetableseed material in such glue and from 2 to 5 pounds of zinc sulphate topounds of the proteinaceous material in the resultant glue.

9. An adhesive composition comprising adding to 99.90 pounds of soyabean flour 0.10 pound of a secondary alkyl sulphate of the class confrom12 to 1'7 carbon atoms inclusive, about 330 pounds of water, 8 pounds ofcaustic soda dissolvedin 10 pounds of water, seven pounds of limesuspended in 25 pounds of water, 25 pounds of sodium silicate and 2pounds of carbon bisulphide. v

10. An adhesive composition comprising adding to 97.4 pounds of soyabean flour 0.1 pound of a secondary alkyl sulphate of the classcontaining'from 12 to 17 carbon atoms inclusive, 2.5 pounds of zincsulphate, about 360' pounds of water, 8 pounds of caustic soda dissolvedin 10 pounds of water, 7 pounds of lime suspended in 25 pounds of water,25 pounds of sodium silicate and 2 pounds of carbon bisulphide.

11. An adhesive composition which comprises adding to 87.4 pounds ofsoya bean flour 5 pounds of casein, 5 pounds blood albumin, 0.10 poundof a secondary alkyl sulphate of the class containing from 12 to 17carbon atoms inclusive, 2.5 pounds of zinc sulphate, about 360 pounds ofwater, 8 pounds. of caustic soda dissolved in 10 pounds of water, sevenpounds of lime suspended. in 25 pounds of water, 25 pounds of sodiumsilicate and 2 pounds of carbon bisulphide.

DAVIS MILLER WOOD.

, CERTIFICATE OF CORRECTION. Patent No. 2,297,5L 1, a September 29, 19L2.

- DAVIS MILLER WOOD.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 5,first column, line 2+, for "dibromate" read -dichromate---; and secondcolumn, line 5', strike out the word "pounds"; and that the said LettersPatent should be read with this correction therein that. the samemayconform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of December, A. D. 1914.2.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

